# Effects on the CMB from magnetic field dissipation before recombination

## TL;DR

This paper investigates how magnetic field dissipation before recombination influences the cosmic microwave background's anisotropies and polarization, highlighting effects of weak magnetic fields with specific spectral properties.

## Contribution

It introduces a detailed analysis of the impact of pre-recombination magnetic field damping on CMB anisotropies and polarization, considering different spectral indices and field strengths.

## Key findings

- Magnetic fields less than 0.1 nG can significantly affect CMB anisotropies.
- Negative spectral indices enhance the magnetic field's impact on the CMB.
- Dissipation of magnetic fields influences the thermal and ionization history of the universe.

## Abstract

Magnetic fields present before decoupling are damped due to radiative viscosity. This energy injection affects the thermal and ionization history of the cosmic plasma. The implications for the CMB anisotropies and polarization are investigated for different parameter choices of a non helical stochastic magnetic field. Assuming a Gaussian smoothing scale determined by the magnetic damping wave number at recombination it is found that magnetic fields with present day strength less than 0.1 nG and negative magnetic spectral indices have a sizeable effect on the CMB temperature anisotropies and polarization.